There are all types of applications you use every day which only require single sign on authentication. Whenever you enter in a user name and password, you are using this type of authentication. The thing to be aware of is that using single sign on is not the most secure method available. Some users will use the same user name and password for every application they need to log into, which increases the chances someone can hack their user name and password.
Some Single Sign on Authentication Applications Will Store User Names and Passwords
Another problem with single sign on authentication is when different applications offer to store your user name and password. Users are quick to check the box or click the button allowing the application to do this, which allows them to never have to enter their user name or password, whenever they use the application. This means anyone can access the application from the user’s computer. One way around this problem is to use two factor authentication, which will ask for a second form of authentication before granting access to the application.